3+ Mawbyite PbFe2 (AsO4)2(OH)2 c 2001-2005 Mineral Data Publishing, version 1 Crystal Data: Monoclinic. Point Group: 2/m. Crystals, to 0.2 mm, show {101}, {110}, {001}, “dogtooth” to prismatic k [001]; typically in hemispherical, cylindrical, and spongy sheaflike aggregates, druses, and crusts. Twinning: “V”-shaped, about {100}, common. Physical Properties: Cleavage: On {001}, good. Fracture: Conchoidal. Hardness = ∼4 D(meas.) = n.d. D(calc.) = 5.365 Optical Properties: Transparent to translucent. Color: Pale orange, orange-brown to reddish brown. Streak: Yellow-orange. Luster: Adamantine. Optical Class: Biaxial (–). Pleochroism: Faint; brown to reddish brown. Orientation: Y = b; X ' c. α = 1.94(2) β = 2.00(2) γ = 2.04(2) 2V(meas.) = 80(5)◦ Cell Data: Space Group: C2/m. a = 9.066(4) b = 6.286(3) c = 7.564(3) β = 114.857(5)◦ Z=2 X-ray Powder Pattern: Broken Hill, Australia. 4.647 (100), 3.245 (100), 2.724 (70), 2.546 (50), 2.860 (40), 4.458 (30), 3.136 (30) Chemistry: (1) (2) (1) (2) P2O5 0.23 ZnO 0.82 As2O5 34.90 36.44 PbO 37.91 35.38 Al2O3 0.02 H2O [2.46] 2.85 Fe2O3 23.66 25.33 Total [100.00] 100.00 (1) Broken Hill, Australia; by electron microprobe, total Fe as Fe2O3, H2Oby difference; corresponds to Pb1.11(Fe1.94Zn0.07)Σ=2.01[(As0.99P0.01)Σ=1.00O4]2(OH)1.79. (2) PbFe2(AsO4)2(OH)2. Polymorphism & Series: Dimorphous with carminite. Mineral Group: Tsumcorite group. Occurrence: In an arsenic-rich reaction halo in fractures and cavities in a spessartine-quartz rock in the oxidization zone of a metamorphosed stratiform Pb–Zn orebody (Broken Hill, Australia); in the oxidization zone of Ag–Pb–Cu–Bi mineralization in fluorite–barite–quartz veins (Moldava, Czech Republic). Association: Corkite–beudantite, adamite–olivenite, duftite, bayldonite, hidalgoite, pharmacosiderite, segnitite, Fe–Mn oxides (Broken Hill, Australia); mimetite, philipsbornite, thometzekite (Moldava, Czech Republic). Distribution: In the Kintore open cut, Broken Hill, New South Wales, Australia. From Moldava, 20 km northwest of Teplice, Czech Republic. In Germany, from the Clara mine, near Oberwolfach, the Silberbr¨unnlemine, near Gengenbach, and in the St. Josef mine, Schuttertal, Black Forest; from Oberwiesenthal, Saxony. Name: To honor Sir Maurice Alan Edgar Mawby (1904–1977), Chairman of CRA, Ltd., for his contribution to the Australian mining industry and preservation of Broken Hill minerals. Type Material: South Australian Museum, Adelaide, G16062, G16066; Museum Victoria, Melbourne, Australia, M39065, M39068, M39173, M39178. References: (1) Pring, A., E.M. McBriar, and W.D. Birch (1989) Mawbyite, a new arsenate of lead and iron related to tsumcorite and carminite, from Broken Hill, New South Wales. Amer. Mineral., 74, 1377-1381. (2) Kharisun, M.R. Taylor, D.J.M. Bevan, A.D. Rae, and A. Pring (1997) The crystal structure of mawbyite, PbFe2(AsO4)2(OH)2. Mineral. Mag., 61, 685–691. (3) Krause, W., K. Belendorff, H.-J. Bernhardt, C. McCammon, H. Effenberger, and W. Mikenda (1998) Crystal chemistry of the tsumcorite-group minerals. New data on ferrilotharmeyerite, tsumcorite, thometzekite, mounanaite, helmutwinklerite, and a redefinition of gartrellite. Eur. J. Mineral., 10, 179–206. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise without the prior written permission of Mineral Data Publishing..